The present invention relates to a wiper rubber for windshield wipers, and also to use of the wiper rubber.
Conventional wiper blades for windshield wipers are blades manufactured from rubber materials which have not only high resistance to ozone and UV radiation but also in particular high abrasion resistance and a low coefficient of friction on a glass pane requiring cleaning. The only way of complying with this demanding requirements profile is to use a suitable selection of the rubber materials used, and also to use suitable processing conditions. In particular here, stringent requirements are placed upon the processing auxiliaries used to provide a suitable degree of crosslinking during the vulcanization of the corresponding rubber material. These are in particular substances that function as sulfur donors to form sulfide bridges or that function as vulcanization accelerator system.
Ethylenethiourea (ETU) is nowadays used for vulcanizing rubber mixtures made of natural rubber and chloroprene. It accelerates the hardening of both natural rubber and of polychloroprene. However, the use of ETU is undesirable for occupational health reasons, because of its suspected teratogenicity and/or carcinogenicity.
It is also known that tetramethylthiuram disulfide (TMTD) can be used as sulfur donor for vulcanizing rubber materials. The mechanism of action of that compound is based on releasing nitrosamines, which are likewise hazardous to health.
There are also alternative rubber materials disclosed in U.S. Pat. No. 6,495,625 B1, comprising a crosslinking agent, and also a vulcanization accelerator.